A simple system for improving the accuracy of IZC bone screw placement

Abstract

An operator often finds it hard to assess the ideal timing to start angulating the driver while placing infrazygomatic crest screws. Thus, we have designed a simple system to guide the operator to know exactly when the angulation of the driver should be started for the ideal placement of the IZC screw. The components of the system include the calculation of the amount of tissue that needs to be pierced perpendicularly and the fabrication of an indicator device over the implant driver with a stainless steel wire. Hence, using this system, the proper timing for angulation can be obtained, thus improving the accuracy of placement.

Clinical applicability of IZC’s in orthodontics - A review

“…Hence, the recommended insertion angle as per the studies is between 55 o -70 o . 10 (Figure 3) But the failure of changing the angulation at the exact time results in: 12 1. Inaccurate ideal final angulation, leading to trauma to the buccal mucosa 2.…”

“…According to Jia et al (2018) 15 the penetration through double cortical bone plates with limitation of the penetration depth within 1 mm is recommended for infrazygomatic crest mini-implant anchorage. 2,10,12,15 Among the two sizes of IZC screws i.e., 12 and 14 mmwhen the soft tissue in the buccal vestibule is thick the ideal choice is a 14 mm screw (7 mm head + collar area and 7 mm cutting spiral) whereas the screw of 12 mm is an ideal choice in cases where soft tissue is thin in the vestibular region. However, variations exist in the length of cutting spiral, head, and collar dimensions depending on the choice of manufacturer.The shape of the head of screw may also vary, the common being the mushroom shaped and as a short or a long collar depending on the anatomic site and the clinical situation it needs to be used for.…”

EZC Guidance for Bone Screws: A Chairside Solution

“…asymmetrically placed IZC screws on the left and right side of the mouth can lead to alteration of biomechanics. 2…”

“…When this is achieved, the operator then needs to start angulating the screw (Figure 3) (cortical bone thickness: 1.44 ± 0.39 in adolescents, 1.58 ± 0.34 in adults). 2…”

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asymmetrically placed IZC screws on the left and right side of the mouth can lead to alteration of biomechanics. 2 A clinician usually finds it challenging to find a purchase point of the cancellous bone and to place it at the correct angulation, which needs to be achieved for the success of the bone screw.Herein, fabrication of a guide for the accurate placement of the IZC screws, using the basic armamentarium available in a clinic, is demonstrated. The method is economical, quick, non-tedious and accurate.Armamentarium: 19*25 stainless steel wire, universal plier, symgrid, IZC screw, and the implant driver.Absolute anchorage systems have stormed the world of orthodontics over the past two decades with their ability to produce skeletal anchorage, converting borderline surgical cases into non-surgical and extraction cases into non-extraction or even bringing about the aesthetic impact which was difficult to achieve by conventional mechanics.

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